Roy,, A. E., & Clarke,, D. (2011). Astronomy: Principles and Practice (4.). Institute of Physics.
Citación estilo ChicagoRoy,, A E., and D. Clarke. Astronomy: Principles and Practice. 4. Bristol: Institute of Physics, 2011.
Cita MLARoy,, A E., and D. Clarke. Astronomy: Principles and Practice. 4. Institute of Physics, 2011.
Warning: These citations may not always be 100% accurate.